Knife-feeding arrangements for sickleshaped knives in cut-offs



May 7, 1963 D. w. MoLlNs ETAL 3,088,510

KNIFE-EEEDING ARRANGEMENTS FoR sIcxLE-SHAPED KNIVES 1N cuT-oFFs Filed June 7, 1961 6 Sheets-Sheet 1 &\\ A

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KNIFE-FEEDING ARRANGEMENTS FOR sIcxLE-SHAPED KNIVES 1N cuT-oFFs 6 Sheets-Sheet 2 Filed June '7, 1961 A TToR/ve g May 7, 1963A D. w. MoLlNs ETAL KNIFE-FEEDING ARRANGEMENTS FOR sIoxLE-SHAPED KNIVES IN CUT-OFFS 6 Sheets-Sheet 5 Filed June '7, 1961 41117. am on l l 11./ A NN QC MQ mm @m E mm Nm f L NN m E. om Bmw QN .wmf

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ATTORNEYS KNIFE-FEEDIN ARRANGEMENTS FOR SICKLE-SHAPED May 7, 1963 D w. MoLlNs ETAL 3,088,510

KNIVES IN CUT-OFFS Filed June 7, 1961 6 Sheets-Sheet 4 MMM/77 BY QM ff MM Ma@ M, M, Jah/ A TToRNz-L Y) May 7, 1963 D. w` MoLlNs ETAL KNIFE-FEEDING ARRANGEMENTS FOR SICKLE-SHAPED KNIVES IN CUT-OFFS 6 Sheets-Sheet 5 Filed June 7, 1961 ATTORNEYSr May 7, 1963 D. W. MoLlNs KNIEE-FEEDING ARRANGEMENTS vEs IN CUT- ET AL 3,088,510 FOR sIcxLE-SHAPED oFFs KNI 6 Sheets-Sheet 6 Filed June 7, 1961 i 3 6 7 /mm 5 N 9 E u m 0. l MO States ate i1;

3 088,510 KNIFE-FERDING ARRANGEMENTS FR SICI/LE- SHAPED KNIVES IN CUT-@FFS Desmond Walter Molins and .lames Arthur Mason, Deptford, London, Engiand, assiguors to Molins Machine Company Limited, a British company Filed .lune 7, 1961, Ser. No. 115,354 Claims priority, application Great Britain ll'une 8, 1960 Claims. (Cl. 1146-95) This invention concerns improvements in knife-feeding arrangements for knives in cut-offs of cigarette-making machines, said knives being of the kind having a cutting edge which is eccentric to the axis of revolution of the cut-off. Such knives are commonly termed sickleshaped knives and this `term is used hereafter for brevity.

As is well known these knives are lightly ground at each revolution of the cut-off mechanism, that is, once per cigarette cut, and consequently they wear out rather quickly and it is necessary to provide means for feeding the knife outwards from its carrier so as to compensate for the wear.

According to the invention there is provided a knifefeeding device for a cigarette machine cut-off having a sickle-shaped knife, as dened above, comprising a knife clamp frictionally gripping the knife, an abutment engaging the knife near its inner end and means for moving the abutment to feed the knife outwards from the axis about which the cut-off rotates and against the friction of the clamp, said means comprising a flexible member attached to said abutment and means for moving said flexible member to move the abutment and the knife outwards from the said axis.

The iiexible member may 'be attached to a nut and a screw threaded into the nut may be rotated to cause said member to be moved to effect the knife-feeding movement. A chain is a suitable flexible member.

The iiexible member may be a chain attached to both sides of the nut and guided around pulleys and the abutment may be shaped to enter an aperture in the knife to provided driving engagement therewith.

Alternatively an end of the member may be attached to a support engaging the inner end of the knife so that if the nut is moved to exert tension on the member the knife will `be moved outwards against the friction of the clamp. In this case however the clamp should be adjustable to prevent centrifugal force, which is considerable at the rate these cut-offs rotate, from throwing the knife outwards and causing it to leave the support.

Rotation 4of the screw may be effected by gearing driven by the mechanism which drives the cut-off.

Alternatively the screw may be driven through a gear train of low velocity ratio said train comprising a gear wheel fixed -to a shaft on which the cut-off revolves and rotatable therewith, a countershaft having two gear wheels iixed to it, one engaging the iirst said gear wheel, a further gear wheel rotatably mounted on said shaft and coupled to the said screw and engaging the other gear wheel on the countershaft, said train having gear wheels of such numbers of teeth that the product of driving and driven teeth is substantially equal but not exactly equal.

The gear wheel coupled to the screw may be coupled thereto by being attached to a shaft passing through the first said shaft and having a bevel gear wheel at one end, the screw being provided with a bevel gear wheel engaging the lfirst said Ibevel gear wheel. In this construction a Geneva stop -device may be provided to check the rotation of the screw when the nut has reached the end of its movement along the screw and the attachment between the gear wheel coupled to the screw and the shaft having the second said bevel wheel at one end may be through an overload clutch arranged 4to break when the Geneva stop checks the rotary movement of the screw. The nut may be returned to its original position by manual rotation of the screw as the said clutch -Will break at each revolution of the screw.

Two constructions according to the invention are shown in the accompanying drawings, one having an independent drive for the knife feeder and the other deriving the knife feeder motion from the motion of the cut-oif device itself.

In the drawings:

FIGURE 1 is a sectional elevation of the iirst construction;

FIGURE 2 is a top plan of part of FIGURE 1, partly in section, and showing `further parts of the mechanism not visible in FIGURE l;

FIGURE 3 is an enlarged view of the knife and its chain feeder means shown in FIGURE 1;

FIGURE 4 is an elevation of the second construction, partly in section;

FIGURE 5 is a plan of par-t of FIGURE 4 as viewed on the section line 5 5;

FIGURE 6 is a view of a fragment of FIGURE 5 and is a section on the line 6 6;

FIG-URE 7 is a view of a fragment of FIGURE 4 and is a section on the line 7 7;

FIGURE 8 shows a modied knife-feeding arrangement;

FIGURE 9 is a fragmentary view of the right-hand end of FIGURE 4 but illustrating a modified construction of a clutch;

FIGURE l0 is a view looking at the right-hand end of FIGURE 9 showing details of the clutch.

Referring to FIGURES 1 to 3 the cut-off -to which the invention is applied is of Ithe kind described and claimed in United States patent specification No. 1,860,- 197 and is only briefly described here.

A shaft 10 is journalled in a box 11 and driven from a gear wheel 12 to rotate at one revolution per cigarette to be cut. At 13 there is pivoted to the shaft 10 a knife carrier 14 and this is in turn pivoted at 15 to a fork 16 which has a shaft 17 journalled and freely rotatable in a bearing block 18. This block is adjustable on a fixed bracket 19 having a curved face so that the angle between the axes of shafts 10 and 17 can be varied. This adjustment causes the traverse of a knife 20 attached to the carrier 14 to be altered.

The linear speed of the cigarette rod in the cigarette machine on which this cut-off is used is normally kept constant and different lengths of cigarette are obtained by altering the speed of rotating of the shaft 10; the longer the cigarette the more slowly the shaft revolves. Thus the knife to cut a long cigarette takes longer to pass through the rod and the traverse of the knife must be altered to suit. In other words during the timel the knife take to pass through the rod the rod has advanced by a certain amount and the knife traverse must, during cutting, equal this amount.

Other features of the normal cut-olf are a grinding disc 21 and a similar disc 22 for removing any burr caused by grinding.

The knife 20 as best seen in FIGURE 3 is supported by a block 23 and held frictionally between plates 24 and 25. The block can be raised in a guide 26 by a chain 27 which passes around pulleys 28 and is attached to an eyebolt 29 in the block 23. Thus, as the chain 27 is pulled, the knife will be moved outwards from the axis of shaft 17, sliding through the friction clamp formed by plates 24 and 25. lIt will of course be understood that the knife movement is extremely slow. The chain 27 draws the knifel supporting block 23 outwards from the axis of the shaft 17 against the pressure of a pair of springs 52 (one only shown) surrounding rods 53 arranged at each side of the chain 27. When the tension on the chain is relaxed the block 23 will move inwards again.

The chain 27 leads down towards the axis of the shaft 17 where it passes around another pulley 30 and is then fastened to an eye in a short rod 31 which is supported in a freely rotatable bearing 32 so. that the shaft 17 can rotate around the rod 31 without causing any appreciable friction. Another chain 33 is fastened to a member 3.4 which is screwed to a housing `35 which constitutes the bearing 32 and this housing is itself freely rotatable in a further bearing 36. inside the shaft 17. As shown, the bearings consist of two rings of balls, this being the most suitable construction.

The chain 33 passes around a pulley 37 journalled in the bearing block 18 and then outwards over another pulley 38, see FIGURE 2, and the end is fastened to a plate structure 39. This` structure is guided in grooves 40 in a forked bracket 41 by lugs 42 which slide in the grooves 40 and in the middle of the housing is a screw 43. This is threaded into a nut 44 held captive within the plate structure 39 but capable of rotation therein at times. Normally the nut is held aganist rotation by a key 45 engaging a flat on the nut. The screw 43 is rotated by a -sprocket wheel 46 connected by a chain 47 in another sprocket wheel 48 mounted on a shaft 49 projecting from the box 11 and driven from the gear wheel l12 by suitable gearing inside the box. Sprocket wheel 46 is the input and screw 43 the output of a reductionV gear 109. When the knife has been fed outwards to the maximum amount and is replaced, the key 45 is removed and the nut 44 which has knurled shank is turned by hand to bring it out towards the free end of the screw 43 and the cut-off is again ready for use.

Thus as the cut-off rotates, the knife 20 is slowly moved outwards at a rate depending on the gearing between the gear wheel `12 and the screw 43, and the pitch of said screw. This rate could be readily altered if necessary by changing one of the sprocket wheels 46 and 48.

Referring now to FIGURES 4 to 7 the cut-off is of the same construction so the same references are used for similar parts as the differences in detail construction are of no` essential importance and there is no need to repeat the description of said parts. In this construction a short chain 50 passing` around pulleys 51 draws the knife supporting block 23 outwards from the axis of shaft 17 against the pressure of the springs 52 as in the previous example.

An end of the chain 50 is attached to a nut 54 threaded on to a screw 55 and at its inner end this screw has a mitre wheel 56 attached to it which mates with another mitre wheel 57 fixed on a shaft 5S. This shaft is rotatable within the shaft 17. as will now be explained.

Four gear wheels 59, 60, 61 and 62 are arranged` as shown in FIGURE and have 219, 220, 221 and 220 teeth respectively. The gear wheel 62 has a pawl 63, best seen in FIGURE 6, pivoted to it at 64 and drawn into engagement with a clutch collar 65, which is keyed to the shaft 58, by a spring 66. The gear wheel 59 is keyed to the shaft 17 and thus rotates at the same speed, while the gear wheels 60 and 61 are attached to a countershaft 67 and revolve at equal speeds. The gear wheel 62 is rotatable relatively `toA the shaft- 17, being journalled on the shaft 58 but rotating therewith as long as the pawl 63 is in engagement with the clutch collar 65. The gearing described results in a very slight angular displacement per revolution between the wheels 59 and 62.

The mitre wheel 57 is rotating on its axis at a speed only slightly dierent from the speed of rotation of the carrier 14 and thus the planetary motion of the mitre wheel 56.is almost the same as the axial rotation of the mitre wheel 57, but, owing to the slight difference in the speed of the mitre wheel 57, the mitre wheel 56 receives a tiny axial motion and so the screw 55 is rotated. The combination of the gearing described and the screw is such that the knife moves outwards by about a millionth of an inch per revolution of the cut-oi.

In order to prevent damage to the nut 54 when it reaches the inner end, FIGURE 4, of the screw 55, a short shaft 68 is fixed to the screw 55 and has a small gear wheel 69 at its lower end. This mates with another gear wheel 70 and to each wheel there is fixed a disc 71 and 72 respectively, each provided with a sector-shaped protuberance 73 and 74 respectively, see FIGURE 7. These sectors operate like` a Geneva stop and at the beginning when the nut 54 is in its outward position the sectors are clear of one another and as the wheels 69 and 70 rotate the sectors separate still further. At the end of the run, that is, when the knife 20 has been fed outwards to the limit of its movement, the sectors will foul one another and the clutch 64-65 will.` break.

The restoration of the nut 54 to its inner position is effected by applying a Spanner to a hexagon 75 formed on the outer end of the screw 55 and rotating the screw to move the nut, the clutch pawl 63 clicking over the collar 65 meanwhile.

Referring to FIGURE 8 the nut 54 and screw 55 are as in FIGURE 4, but the flexible member, marked 150, is attached to both ends of the nut and is guided around four pulleys 151. Instead of support block 23 there is provided an abutment 123 which is attached to the chain and has a small lug entering a slot in the inner end of the knife 20. In this way centrifugal yforce due to the mass of the rotating knife cannot displace the knife whereas in the earlier constructions the knife could possibly` be displaced by this force and disengage from the block 23, although the friction clampl is made adjustable to avoid this.

As in the specification referred to the knife carrier `14 could have a knife at each end in which case the knifemoving parts are duplicated and operated by another mitre wheel, like 56, placed at the opposite side. would involve shifting the Geneva stop device to the outer end of the screw 55 and some local rearrangement of thc parts. Further it will be apparent that any suitable type of gear wheels, for example bevel gear wheels, may be substituted for the spur gear wheels 59, 60, 61, 62 in FIGURE 5.

By` multiplying the numbers of driving and driven teeth in the figures given it wil be seen that the wheel 62 rotates 48,400 times` while the wheel 59 (and the cut-olf shaft) rotates 48,399 times and that there is only a microscopic difference in the rates of rotation of the two wheels. If a iiner or coarser rate of feed of the knife is required (for a given screw) it is only necessary to alter the teeth numbers while keeping to the same differences between them. For example if a basic figure of aroundy 300 teeth is adopted the teeth numbers would be 299-300-301-300- for 59, 60, 61 and 62 respectively and wheel 62 would rotate 90,000 times while the wheel 59 rotates 89,999 times.

With larger differences in teeth numbers the speed reduction would be less and while larger differences are possible, in view of the center-distance tolerance possible with involute teeth, differences of 1 tooth between each pair will give almost any desired reduction and the center distances can remain correct and noise and wear` avoided.`

It is clear that the screw should have a reasonable pitch, that is, not too small, as the nut will traverse it a great many times in the course of a year and undue wear and tear are to be avoided.

Referring now to FIGURES 9 and 10 the clutch previously described with reference to the earlier figures is satisfactory in its operation but it has a slight drawback in that as the cut-off continues to revolve after knife feeding has ceased because of the Geneva stop a long time must elapse before the clutch pawl is in a position to slip into the notch under the action of the spring. To avoid this the clutch may be constructed as shown in FIGURE 10 where equivalent parts to those previously This illustrated have the references increased by 100. The clutch pawl 163 pivoted at 164 has a sharp-pointed tooth 163A at its free end. The clutch collar 165 is notched all around its periphery with notches corresponding in shape to a sharp tooth 163B on the pawl. A locking pawl 167 pivoted at 168 and having a longtajl 169 is provided. When the clutch breaks the sharp tooth 163A will engage with a notch in the neighbouring end of the locking pawl and hold the clutch pawl out of engagement with the collar. An abutment 17.1 is provided having a stem 172 which is slidable in the gear housing and held in the position shown by a light spring 173. The outer edge of the locking pawl is eccentric after the clutch has broken. After a new knife has been fitted and the cut-off is set into motion again the stem `172 can be pressed down by a knob 174 and the tail of the locking pawl will strike the abutment and the pawl will be turned on its pivot to release the clutch pawl so that its tooth can enter a neighbouring notch in the clutch collar. As above remarked the clutch collar in this example is notched all around. This means that the clutch pawl can move into engagement with a notch in the collar after a fairly short time when the cut-off starts to revolve. With the earlier arrangement the distance between the notches made clutch re-engagement a very slow process as the difference in speed between the shaft 17 and gear wheel 62 is exceedingly small and naturally when the clutch is disengaged the shaft 58 will revolve at the same rate as the shaft 17. As the cut-off shaft is rotating a fraction faster than the wheel 62 the sharp tooth 163B is able to slide down the trailing ank of a notch easily and without shock.

In these views the gear wheels shown have the same general function as before but as it was found with the gears illustrated in FIGURES 4 and 5 that the feed rate of the knife was somewhat coarse, many more teeth were cut on the gears, those shown in FIGURE being 100 DP. so that much larger tooth numbers could be used.

What we claim as our invention and desire to secure by Letters Patent is:

1. A knife-feeding device for a cigarette machine cut off mounted on a rotatable shaft and having a knife, comprising a knife clamp frictionally gripping the knife, an

abutment engaging the knife near its inner end, and means for moving the abutment to feed the knife outwards from the axis about which the cut-olf rotates and against the friction of the clamp, the said means comprising a flexible member attached to said abutment and to a nut, and a screw threaded into the nut with means driven from said rotatable shaft for rotating the screw to cause said flexible member to be moved to eifect the knife-feeding movement.

2. A knife-feeding device as claimed in claim 1 wherein the dlexible member is a chain attached to both sides of the nut and guided around pulleys and the abutment is shaped to enter an aperture in the knife to provide driving engagement therewith.

3. A knife-feeding device as claimed in claim 1 in which the screw is driven through a gear train of low velocity ratio, said train comprising a gear Nvheel -xed to the shaft on which the cut-off revolves and rotatable therewith, a countershaft having two gear Wheels xed to it, one engaging the first said gear wheel, a further gear wheel rotatably mounted on said shaft and coupled to the said screw and engaging the other gear wheel on the counter shaft, said train having gear wheels of such numbers of teeth that the product of driving and driven teeth is substantially equal but not exactly equal.

4. A knife-feeding device as claimed in claim 3 in ywhich the gear wheel coupled to the screw is coupled thereto by being attached to a shaft passing through the iirst said shaft and having a bevel gear wheel at one end, the screw being provided with a bevel gear wheel engaging the first said bevel gear wheel.

5. A knife-feeding device as claimed in claim 4 comprising a Geneva stop device to lcheck the rotation of the screw when the nut has reached the end of its movement along the screw and in which the attachment between the gear wheel coupled to the screw and the shaft having the second said bevel at one end is through an overload clutch arranged to break when the Geneva stop checks the rotary movement of the screw.

References Cited in the le of this patent UNITED STATES PATENTS 1,914,756 Rosler June 20, 1933 1,991,795 'Debaecker Peb. 19, 1935 1,992,735 Bronander Feb. 26, 1935 FOREIGN PATENTS 463,577 Great Britain Apr. 2, 1937 878,916 Germany June 8, 1953 

1. A KNIFE FEEDING DEVICE FOR A CIGARETTE MACHINE CUTOFF MOUNTED ON A ROTATABLE SHAFT AND HAVING A KNIFE, COMPRISING A KNIFE CLAMP FRICTIONALLY GRIPPING THE KNIFE, AN ABUTMENT ENGAGING THE KNIFE NEAR ITS INNER END, AND MEANS FOR MOVING THE ABUTMENT TO FEED THE KNIFE OUTWARDS FROM THE AXIS ABOUT WHICH THE CUT-OFF ROTATES AND AGAINST THE FRICTION OF THE CLAMP, THE SAID MEANS COMPRISING A FLEXIBLE MEMBER ATTACHED TO SAID ABUTMENT AND TO A NUT, AND A SCREW THREADED INTO THE NUT WITH MEANS DRIVEN FROM SAID ROTATABLE SHAFT FOR ROTATING THE SCREW TO CAUSE SAID FLEXIBLE MEMBER TO BE MOVED TO EFFECT THE KNIFE-FEEDING MOVEMENT. 